Japan Meteorological Agency (JMA) image shows Tropical Storm Ma-on, July 19, 2011.

The former Typhoon Ma-on, now a tropical storm, has brushed land in southern Japan, unleashing high winds and torrential rain.

Ma-on is now on a track that will bring its center, and thus its most serious wind and rain, significantly south of Tokyo, and well south of the stricken Fukushima nuclear plant in northeastern Japan. However, wind and rain will still affect Fukushima.

Radar imagery shows center of Tropical Storm Ma-on (lower left) near Cape Muroto, Shikoku, Japan, on July 19, 2011 (JMA image).

The tropical storm’s center was located at Cape Muroto, on island of Shikoku, Tuesday evening, local time (Tuesday morning, Eastern Time), according to analysis and radar imagery of the Japan Meteorological Agency (JMA). Highest sustained winds were down to 55 mph, or less than 65 mph, the Joint Typhoon Warning Center (JTWC) advised.

Strong winds were lashing parts of the island of Shikoku along with the Kii Peninsula of southernmost Honshu.

More important than the winds has been the rain, which continued to fall torrentially in areas near and ahead of the storm’s path. The heaviest flooding rain was pelting highlands of eastern Shikoku and the Kii Peninsula, where more than 12 inches fell, weather observations on the JMA website indicated.

Official warnings for heavy rain, flooding and mudslides were posted by the JMA for most of central and southwestern Japan as of Tuesday evening, local time.

Going forward through Tuesday, ET, Ma-on will weaken further as clips Honshu’s Kii Peninsula. The tropical storm will then veer southward to open water, thereby skirting greater Tokyo on its way to the remote northwest Pacific Ocean.

Ma-on’s most serious threat to life and property through Wednesday will stem from its persistent torrential rain between the Kii Peninsula, south of Osaka, and Tokyo. Most of the excessive rain will fall along the area’s mountains.

Wind impact will be relatively small.

At Fukushima, in northeastern Honshu, the site of the damaged nuclear power plant will be subject to rain, some heavy, with rainfall potential of 2 to 4 inches through Wednesday. Minor flooding such as ponding of water will be likely.

Winds will reach 30 to 40 mph at the site. Stronger winds at sea will bring rough waves, which could have adverse impact in the area. The tsunami-damaged plant is located directly on the east-facing coast.

After Wednesday, the storm will leave Japan, taking any adverse rain and wind with it.

On Monday, workers at the site were busy making ready for the storm’s inclement weather, according to CNN. Work involved building a protective cover over the plant’s turbine building, the roof of which was holed during the explosions that followed a great quake and massive tsunami in March. The cover was to keep rain out of the building, CNN indicated.

The explosions rattled reactor buildings, releasing radioactive matter and initiating the most serious nuclear crisis since Chernobyl in the former Soviet Union.